Polyvinyl chloride plasticized with an ester and a petroleum extract



Patented Dec. 25, 1951 UNITED STAT POLYVINYL CHLORIDE PLASTICIZED WITH AN ESTER AND A PETROLEUM EXTRACT Eric William Musther Fawcett and Albert Millien,

Sunbury-on-Thames, England, assignors to Anglo-Iranian Oil Company Limited, London, England, a British joint-stock corporation No Drawing. Application December 8, 1943, Se-

rial No. 513,468. In Great Britain .October 28,

Section 1, Public Law 690, August 8, 1946 Patent expires October 28, 1962 1 Claim.

This invention relates to the production oi plasticised polyvinyl chloride or polyvinyl chloride co-polymers suitable for use for example as coating compositions, cable dielectric compounds, and moulding compositions.

The employment of such substances as tricresyl phosphate, dibutyl phthalate and dibenzyl sebacate as plasticisers for polyvinyl chloride or its co-polymers has long been practised. These plasticisers are polar in character, and as such are known to have an adverse effect on the electrical and water resistant properties of the polymers. In addition, other physical properties, for example tensile strength are also known to depreciate rapidly with increasing additions of the plasticiser to these polymers.

We have now found that certain hydrocarbons which have good electrical and water resistant properties because of their tion-polar character, are compatible with polyvinyl chloride and many polyvinyl chloride co-polymers such as the co-polymers of vinyl chloride with vinyl acetate, methyl acrylate, vinylidene chloride and the like and act as fillers and partial plasticisers in such polymer compositions as are used for moulded and other goods particularly where a highly plasticised and extensible structure is not desired.

It has also been found that these hydrocarbons are compatible with vinyl polymers of the type specifically referred to, incorporated with known plasticisers, as for example, tricresyl phosphate. A considerable saving may thus be effected in these more costly known plasticisers, since large proportions of the hydrocarbons referred to may be used with small proportions of known plasticisers to yield a polymer compound of superior electrical properties and of the plasticity and extensibility normally required in extrusion stocks such as cable insulating compositions.

The invention therefore relates to a method for the production of plasticised polyvinyl chloride or polyvinyl chloride co-polymer compositions, comprising the addition as a filler or as a filler and plasticiser, either alone or with known plasticisers in smaller proportion, of high molecular weight hydrocarbon materials derived or extracted from mineral oil distillates or residues by selective solvents of a polar character, such as sulphur dioxide, sulphur-dioxide benzole mixtures, alcohols, furfural and phenols. The extracted material may be further treated by distillation, selective absorption and'desorption on suitable absorptive materials or by other known means prior to admixture with the polymeric substance.

' Hydrocarbon materials that geously be used according to the invention are characterised by a high carbon content and thus their molecules contain an the average at least .6 atom of carbon per atom of hydrogen and are generally unsaturated and may contain up to two unsaturated linkages per molecule. The materials may also contain a minor proportion of sulphur and/ or nitrogen in combined form. The molecular weight of the hydrocarbons is in the approximate range 200-800 and preferably in the range 250-750, but higher or lower molecular weight materials may be used in particular cases.

The initial and final boiling points of the hydrocarbons preferred are in the range 250-800 C. at 760 mm. Hg. These hydrocarbons are unlike the normal plasticizers employed in known compositions in that they are non-polar and are not oxygenated, and their insulating and dielectric properties and resistance to moisture are much superior to those of plasticisers of a polar character. In addition these new materials, when added to polyvinyl chloride or polyvinyl chloride co-polymers, do not reduce the tensile strength of the polymer to the same extent as a corresponding proportion of a known plasticiser such as those already referred to. These hydrocarbon materials are therefore valuable'plasticisers or fillers for polyvinyl chloride polymers since they can be used in large quantities either alone, or as a substitute for the greater part of plasticisers normally used, while imparting superior properties to the products.

According to the invention a mineral oil fraction or residue, generally having an average molecular weight in the range 200-800, is first extracted with a selective polar solvent or a mixture of solvents one at least being of a polar character as for example. a mixture of sulphur dimay advantaoxide and benzole. The desired hydrocarbons are 'to be found in the extract phase and are obtained by removal of the solvent by distilla- 4 by weight added. to 100 parts by weight of polyvlnylchloride. A 4

tion. The extract hydrocarbons after further 1 purification or fractionation may-then be inzccordin g to tli cf i 53 032%1. corporated in a polyvinyl chloride, or polyvinyl t p -f chloride co-polymer composition. This opera- I tion may be carried out in known manner, for g; example by mechanical mixing or by solution so 20 11000 of the polymer and hydrocarbons in a mutual volatile solvent, followed by removal of such sol- 1 vent either by distillation, or in the case-of coat- 7 These figures show how the tensile strength ing compositions by direct evaporation after'the may be maintained by the use of large proporcoating operation. Any additional plasticiser tionsof the hydrocarbon material while eflecting such as tricresyl phosphate or solid filling matel5 aeconsiderable saving in both polyvinyl chloride rial such as carbon black, whiting or wood flour and expensive plasticisers. may be incorporated in the composition in known Example 5.The following table shows the tenmanner to yield a stock having the necessary sile strength of a series of compositions made by physical characteristics for extrusion, moulding the solution method which are heavily plasticised or coating. to yield products having an approximate elonga- The following Examples 1 to 3 illustrate the tion at break point of 300%. The amounts of preparation of hydrocarbon materials for use acpiasticiser shown are in parts by weight added to cording to the invention, while the remaining Ex- 100 parts by weight of polyvinyl chloride. amples 4 to 8 illustrate the practical advantages of the use of those materials.

Example 1.l00 parts by volu ne of a crude pes e om tki tif: 1: gig; .3822? troleum distillate having a boiling range of 360- I lbJSq- 525 C. at 760 mm. Hg are treated with 200 parts by volume of an 85/15 mixture of sulphur dioxide :3 and benzole at 127 F. The material extracted '30 so is' 1,000 is then distilled under high vacuum, giving a I 1,600 yield of light coloured hydrocarbon oil which has a boiling range of 400-470 C. at 760 mm. Hg and These figures show how an increased tensile a m an molecular weight of 330. strength may be obtained by using large propor- Example 2.100 parts by volume of a crude petions of the hydrocarbon materials prepared for troleum residue having aboiling range 400650 C. use according to the invention, while eifecting a at 760 mm. Hg are treated with 220 parts by vol- 50% saving in an expensive plasticiser which is me f at The material known to have an adverse eiiect on electrical and. tracted is distilled under high vacuum. v ng 8 water resistant properties- 2 yield of light coloured hydrocarbon on Example 6.The following example illustrates ing an approximateboiling range of 400 550 C. h use of 3 mer ma;teria1s1 in Poly and a mean molecular weight of 420. i' chloinde. composltmns mamly Example 3.100 parts by volume of a crude pegr gg z high tensile sttiength i the troleum distillate having a boiling range of 390- 46 I 430 C. at 760mm. Hg were treated with 200 parts Pans b i ht t h dr P t i by volume of a 90/10 mixture of sulphur dioxide 5 355 i g fig gig igg gil g and benzole at l00120 F. The material exgg PM gg 5 l bf i'im'. tracted having a specific gravity 0.986 at 60 F. was further treated with 300% of sulphur dioxide 50 m nn 5 00 at 50 F., and the hydrocarbons extracted by a 40 nil 31200 this second treatment then distilled under high :8 g I gggg vacuum to remove a 10% distillate and leave a nil 40 11800 10% residue. The 80% middle fraction, equivalent to 7.5% by volume on the original starting I material, with a light coloured hydrocarbon oil Example 7.-This example is illustrative of the having a boiling range approximately that of the use of the hydrocarbon materials incorporated starting material, a specific gravity of 1.049 at with small proportions of other plasticisers and F. and a mean molecular weight of 280. with a vinyl chloride-vinyl acetate co-polymer Example 4.The following table shows the 60 pre ared by the co-polymerisation of a mixture of breaking strengths of a series of film composiparts by weight of polyvinyl chloride and 25 tions, made by the solution method, which are parts by weight of vinyl acetate. lightly plasticised to yield products having an The following table shows figures relating to approximate elongation at break point of compositions obtained as films made by the solu- The amounts of plasticisers shown are in parts 65 tion method.

ii firzzarmi i P a b V i ht z 138:2? Parts by weight of polymerteyml according to 3 g glf g ligrength break the invention t 100 polyvinyl chloride..... 50 20 dlbutyl phosphate 1, 580 32 00" 1 l lo i0ilab ymyfiyl chl o de acemte co- $$lfii Example 8.--This example illustrates the use 01' and said composition containing at least 0.7 part these hydrocarbon materials incorporated either by weight of said total plasticizer per part alone or with small proportions of other plassaid polymer; the amount of extract constituting ticisers in polyvinyl chloride compositions, such he m j r p p r n f he Sum of h amoun s as are used for cable insulation and sheathing. of said extract plus said ester, but said propor- The figures given in the following table are on tion being less than that at which the hydrocarcompositions mixed in the normal manner or on bon extract ceases to be compatible in the coma roll mill and subsequently moulded in a platen position.

press at a temperature of about 150 C. 'l'he ERIC WILLIAM MUSTHER FAWCE'I'I. amounts of plasticiser and-stabiliser shown are in ERT MILLIE Hydrocarbon material according to the 100 parts prepared 100 parts prepared 40 parts pre red invention as in Example 3 as in Example 3 as in Examp e 2 Dibutyi phtbalate- 40 parts. Lead silicate stabiliseru. 5 parts. Tensile strength lbJsq. in 2,610 2,300.

Elongation at break, per cent 280 370. Water; absorption after 48 hrs. at 50 C. wt., per 0.34. v v l l i nie resistivity ohms per cm. cube 7.1X10" parts by weight per 100 parts by weight of poly- REFERENCES CITED vinyl chloride- The lfollowin eferences ar f o The invention is generally applicable in the me of this i a: e 0 rec rd in the utilisation of polyvinyl chloride and its co-polymers, it being understood that degree of compati- UNITED STATES PATENTS bility may be determined in known manner by the Number Name Date practical method of preparing a series of composi- 1, 91, 9 om lens y Feb. 3, 1931 tions in varying proportions of the hydrocarbon 7. Dunham Mar. 1, 1932 materials by which the limits beyondwhich the 1,929,453 8 0 Oct. 10, 1933 hydrocarbons cease to be compatible may be 2,135,951 Rostler Jan. 2, 1940 indicated. 2.185. 52 Rostler Jan. 2, 1940 The refined selected hydrocarbons may be thor- 2210434 Rosenthal et 6, oughly incorporated in widely varying propor- $217,918 Rostler '5, 1940 tions with or Without other known fillers or plas- 23171988 Lawson 1940 ticisers such as tricresyl phosphate commonly 2,220,531 Lazar 1 4 used in the production under known conditions 2 223 333 2:3 3g- {gig of 01 vin l coatin com ositions, diele tri l Y p y y g p c c 01' 2,374,067 Alderson Apr. 17, 1945 tiiiisulating compounds and moulding composions, and the invention is broadly applicable in the use of polyvinyl halides and the polyvinyl OTHER REFERENCES chloride comolmers e Carbide & Carbon Chem. Co., Vinylite Cow claim; polymer Resins for Surface Coating, published A plastic composition which comprises polyber 1942. DD- 1 and 27 (Table an vinyl chloride plasticized with a plasticizer compages 15, 16, 39 d 4 prising a compatible ester boiling above C. Plastics catalog ifor 1 4 Published mber at 1 .mm. Hg pressure and a petroleum extract 1, 1942 by Plastics Catalogue Com, N w Yo k.

boiling above 300 C. at 760 mm. Hg pressure ob- N. Y., p 209 to tained by extracting petroleum with a non-re- Shrine! t "Identification of O anic Comactive highly polar solvent; said polymer con- P ds, 2nd lh y. 1940, Pages 3 t0 taining the same percentage of chlorine as in the .De Bell et al., German Plastics Practice," l946.

polymer when first formed by polymerization, Pages 79 and 91. a 

